Coupling Independent Solid Mechanics-Based Systems in a System-of-Systems Modeling Framework

Modularity is essential for ensuring the efficient execution of system-of-systems (SoS) frameworks, demanding the managerial and operational independence of constituent systems. This study explores the feasibility of enforcing displacement compatibility between two interconnected, independent solid mechanics finite element models with a contact interface within an SoS. This work developed an approach that ensures operational independence by delaying displacement compatibility in one of the systems. The lagged system provides a trial displacement input to the leading system, which determines the displacement discrepancy between both systems. This error is used to calculate an equivalent pressure that enforces displacement compatibility between the models. The method was verified by modeling two specimens with a frictionless contact interface and comparing the results against a continuous model assuming a perfect bond between the specimens. Lastly, the method was implemented within an SoS for space habitats and proved effective in ensuring matching displacements at the contact surface between two interacting structural layers. The proposed approach preserves the modularity of coupled systems, avoiding complex iterative procedures and transferring mass and stiffness information between systems. Moreover, it allows the coupled models to be developed in independent coordinate systems, as they only pass scalar, coordinate-independent parameters through the input-output ports.